Expanding food storage container

ABSTRACT

An expanding food storage container includes a base and a cover. The cover includes a support ring and a dome having a side wall closely received in the support ring. The support ring includes spaced tabs extending toward the side wall of the dome. The outer face of the dome sidewall includes a plurality of camming threads and support threads extending outward along helical paths. There is a pair of threads for each tab, with the threads spaced peripherally to closely receive the associated tab therebetween. Rotation of the dome with respect to the support ring causes the threads to ride up or down the tabs, raising or lowering the dome with respect to the support ring. The upper and lower ends of the threads include a horizontal slot which closely receives the associated tab. The tab includes a depression near its end which receives a lock button extending outward from the dome sidewall within the slot. The lock button may be selectively received within the depression to selectively secure the dome in the expanded or collapsed position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending attorney reference number131740-D200, which is incorporated by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates in general to household food storagecontainers. In particular, the present invention relates to an improvedfood storage container which may expand or retract as needed for storageor use.

It is well known to provide a base with cover to store or transportfood. The cover may or course be removed for displaying or serving thefood in the base. One common problem with this arrangement is the needto accommodate different amounts of food. For example, a base may have acover which is slightly domed, defining together an enclosed space forstorage. However, some larger food items, such as a roast or a tallcake, may not fit within this enclosed space. The usual solution to thisproblem is to provide a second cover having a larger dome which willaccommodate the larger food item. This solution has drawbacks as itrequires the purchase of a second cover, as well as increased storagespace needed for the two covers.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an expanding foodstorage container with a base and a cover where the cover mayselectively expand or collapse as needed.

Another object of the present invention is to provide a cover for a foodstorage container which may expand or collapse as needed.

A further object of the present invention is to provide such anexpanding cover which may be locked in the expanded or collapsedpositions.

Yet another object of the present invention is to provide such anexpanding cover which may suspend the entire container and food ineither the expanded or collapsed positions.

These and other objects are achieved by an expanding food storagecontainer. The cover includes a support ring and a dome having a sidewall closely received in the support ring. The support ring includesspaced tabs extending toward the side wall of the dome. The outer faceof the dome sidewall includes a plurality of camming threads and supportthreads extending outward along helical paths. There is a pair ofthreads for each tab, with the threads spaced peripherally to closelyreceive the associated tab therebetween. Rotation of the dome withrespect to the support ring causes the threads to ride up or down thetabs, raising or lowering the dome with respect to the support ring. Theupper and lower ends of the threads include a horizontal slot whichclosely receives the associated tab. The tab includes a depression nearits end which receives a lock button extending outward from the domesidewall within the slot. The lock button may be selectively receivedwithin the depression to selectively secure the dome in the expanded orcollapsed position.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the invention noted above are explained inmore detail with reference to the drawings, in which like referencenumerals denote like elements, and in which:

FIG. 1 is a top perspective view of the collapsible food storagecontainer according to the present invention in the collapsedconfiguration;

FIG. 2 is a top perspective view of the container cover in the expandedconfiguration;

FIG. 3 is an exploded top perspective view thereof;

FIG. 4 is a side view of the container cover the expanded configuration;

FIG. 5 is a detailed cross-sectional view a long line 5-5; and

FIG. 6 is a detailed cross-sectional view a long line 6-6.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a collapsible food storage container accordingto the present invention is generally designated by reference numeral10. The container 10 generally includes a base 12 and a cover 14. Thebase 12 is shown as a generally flat disc in FIG. 1, but couldalternatively be a shallow or deep bowl. The cover 14 may be secured tothe base 12, such as by a peripheral interlocking seal commonly knownfor food storage containers, a series of locking clamp tabs, etc. as areknown in the art. In the preferred embodiment cover 14 is selectivelysecured to base 12 by a known arrangement of a locking tongue 16received within a mating aperture in the base 12, as shown in U.S. Pat.No. D389,018. As will be discussed more fully below, securing the cover14 to the base 12 allows the user to lift the entire unit (with foodinside) using a handle 18 on the top of cover 14.

As the base may be of a variety of forms, and the invention residesmainly in the cover 14, the description below and the majority of theFigures will focus on cover 14. The cover 14 includes a support ring 20upon which is mounted a dome 22, both of which are preferably formed ofa suitable plastic. The support ring 20 generally takes the form of asection of a cylinder, with a cylindrical ring wall 24 having an upperend 26 and lower end 28. As is best shown in FIG. 3, cover 14 includesat least two tabs 30 spaced about the periphery of the upper end 26 andextending radially inward.

The dome 22 includes a generally cylindrical side wall 32 having anupper end 34 and lower end 36. The ring wall 24 and the side wall 32 aresized such that one will closely fit within the other but still allowfree relative rotation and longitudinal movement between the two. Aseries of camming threads 38 extend radially outward from side wall 32and have a helical form as they extend from a position at or near theupper end 34 to the lower end 36 in a manner similar to screw threads.The tabs 30 on the support ring and the threads 38 extend toward oneanother and are sized so as to overlap. The threads 38 are also spacedabout the periphery of the side wall 32 in a like manner correspondingto the spacing of the tabs 30, and it is desired that there be at leastone thread 38 associated with each tab 30. Further, where there is onethread associated with each tab 30, the threads 38 will all be spaced soas to contact a like edge of their associated tab 30. For example, inthe preferred embodiment shown, the threads are right-handed, and whenviewed from above the threads 38 will all engage the tabs 30 at theright hand edge of the tabs 30 such that the camming thread 38 liesabove (rather than below) the tab 30. Stated another way, the cammingthreads 38 will each contact a leading edge 40 of the tabs 30.

Given the overlapping nature of the threads 38 to the tabs 30 it may beenvisioned that the dome 22 is supported by the underside of threads 38resting upon the associated tabs 30 at the leading edge 40. It may alsobe envisioned that manual rotation of the dome 22 relative to thesupport ring will cause the dome 22 to move longitudinally upward ordownward with respect to the support ring 20 in a manner similar to thescrew moving inward or outward during placement or removal. In this way,it may be seen that the cover 14 may be moved from a collapsedconfiguration where the dome 22 is mainly received within the supportring 20 (FIG. 1) to an expanded configuration where the dome 22 extendsupward beyond the support ring 20 (FIG. 2). With this expansion orcollapse, it may be seen that the volume enclosed within the cover 14will increase as the cover 14 expands and decrease as it collapses.

The tabs 30 and the camming threads 38 will support the dome 22 and holdit against gravity relative to the support ring 20. However, the cammingthreads 38 are inclined, and this support may not be as stable asdesired. To help hold the dome 22 in the expanded position, one or moreof the camming threads 38 may transition to a lower resting land 42.Each of the lower resting lands 42 takes the form of a radially outwardledge extending horizontally about a portion of the periphery of thedome side wall 32 parallel to the lower end 36. The depth of the lands42 are preferably equal to that of the camming threads 38. The length ofthe resting lands 42 is such to allow the tabs 30 to be receivedthereunder a sufficient amount so as to provide a stable restingposition against gravity for the dome 22 when in the expanded positionof FIGS. 2 and 4.

While not required, it is preferred that the resting lands 42 be spacedfrom the lower end 36, and that the lower end 36 include a peripheralflange 44 extending radially outward therefrom and having a depthsimilar to that of the lands 42. The spacing between the lands 42 andthe peripheral flange preferably forms a close sliding fit about theassociated tabs 30. This will provide a stable feel for the user when inthe expanded position.

It is also possible to form a lock button 46 protruding radially outwardfrom the dome side wall 32 at a position between the resting lands 42and the peripheral flange 44. The tab 30 would then include a matingdepression 47 extending radially inward. As may be envisioned, rotationof the dome 22 with respect to the ring 20 would cause the tabs 30 tomove into the slots formed between the lands 42 and the flange 44, withcontinued rotation causing the tab 30 to ride over the lock button 46due to elastic deformation until that button 46 is received within themating depression 47. This would serve to selectively hold the dome 22against unintended rotation. Further, the tabs 30 being closely receivedbetween the lands 42 and flange 44 would prevent upward or downwardmovement of the dome 22 relative to the ring 20. In this manner, thecover 14 may be placed into a very secure expanded position. In fact,this can be so secure as to allow carrying of the fully loaded container10 in this expanded position. Even so, the user may manually turn thedome 22 in the opposite direction to cause the tab 30 to again ride overthe button 46 to release the dome and allow it to move to the collapsedposition.

While moving between the expanded and collapsed positions the cammingthreads 38 will support the dome 22 against gravity as described.However, there may be a tendency for the user to lift the dome 22 duringrotation, causing the camming threads 38 to disengage from the tabs 30and giving a loose feel to the container 10. To avoid this, it ispossible to space the camming threads a distance approximately equal tothe length of the tabs 30 (not shown). In this manner the leading edge40 of the tabs 30 would support the under side of a first camming thread38, while a trailing edge 48 of the same tab 30 would be closelyadjacent to the upper side of the next adjacent camming thread 38. Thisarrangement would be repeated about the cover 14. As may be imagined,this would greatly reduce the amount of free vertical movement betweenthe dome 22 and ring 20, forcing a smooth rise and fall of the dome 22with its rotation.

While it is preferred to have this smooth rise and fall with rotation,for reasons made clear below it is not preferred to space the threads 38equal to the tabs 30. Instead, it is preferred that the camming threads38 be spaced twice the length of the tabs 30. To still have this smoothrise and fall, the dome side wall 32 further includes a plurality ofsupport threads 50 extending radially therefrom. These support threads50 are equal in number to the camming threads 38 and have asubstantially identical depth and incline to threads 38, but with eachof the support threads 50 being spaced from its associated cammingthread 38 by a distance just slightly greater than the length of the tab30. As such, there will be an alternating arrangement of camming thread38, support thread 50, camming thread 38, support thread 50, etc. aboutthe periphery of dome side wall 32. In a manner similar to thatdescribed above, the leading edge 40 of a tab 30 will be in closeproximity or contact with the under side of the associated cammingthread 38, while the trailing edge 48 of the tab 30 will be in closeproximity or contact with the upper side of the associated supportthread 50. As with the first described arrangement, this would greatlyreduce the amount of free vertical movement between the dome 22 and ring20, forcing a smooth rise and fall of the dome 22 with its rotation.

In a manner similar to that described above for the camming thread 38,it is preferred that one or more of the support threads have an upperresting land 52 transitioning therefrom, and extending in the oppositeradial direction to that of the lower resting lands 42. The upper lands52 would preferably have a similar length to that of the lower lands 42.As may be envisioned, these upper lands 52 would prevent continuedupward movement of the dome 22 with respect to the ring 20. Alsosimilarly to the previous arrangement, an upper peripheral flange 54extends radially outward from the upper end 34 of the dome side wall 32,thus combining with the upper resting lands 52 creating one or moreslots to receive the tab 30 when in the collapsed position. Also asbefore, a lock button 46 may protrude from the dome side wall 32 withinthis slot so as to selectively mate with a depression 56 in the outerface of the tab 30.

The tab 30 may include one centrally located mating depression, suchthat the depression 47 and the depression 56 are one and the same andwould mate with either the upper or the lower lock button 46. Inpractice, however, this is not preferred, and the tab 30 would includeseparate depressions 47 and 56 each located near a respective end of thetab 30. This is because the tab 30 must ride over the button 46 viaelastic deformation of the tab 30 (or more likely the entire ring wall24). To provide the desired strength, however, it is desired that thetabs 30 be relatively long. As such, it is preferred that the twodepressions be used at positions relatively close to the ends of the tab30 to make this locking function easier to perform for the user.

Yet another variation is preferred for the container 10, this oneallowing improved assembly. As may be envisioned, to initially assemblethe dome 22 with the ring 20 the tabs 30 must elastically deform to rideover either the peripheral flange 44 or the upper peripheral flange 54.To avoid this, it is preferred that the upper peripheral flange bediscontinuous, as shown. In particular, the upper peripheral flangewould be present only in those areas immediately over the upper restinglands 52. This will form gaps or openings in the upper flange 54corresponding to the pairs of threads 38 and 50 which contain the tabs30. As such, the dome 22 could freely fall downward relative to the ring20 when so aligned. When the ring 20 is mounted to the base 12 this isprevented by the base blocking this motion. However, when the cover 14is removed from the base 12, this assembly or disassembly of the dome 22from the ring 20 becomes quite simple.

As may be seen, with this arrangement the dome 22 may be locked ineither the expanded or the collapsed positions due to engagement of thebuttons 46 with the appropriate depressions 47 or 56, and with theresting lands and peripheral flanges fully supporting the tabs 30. Inthis manner, the user may lift, carry and transport the container 10using handle 18 in both the collapsed and the expanded condition.Further, even during the rotating transition between expanded andcollapsed positions the container will feel stable due to the use of thecamming threads 38 and support threads 50 each closely receiving thetabs 30.

From the foregoing it will be seen that this invention is one welladapted to attain all ends and objects set forth above together with theother advantages which are inherent within its structure.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth of shown in the accompanying drawings is to beinterpreted as illustrative, and not in a limiting sense.

1. An expanding food storage container, comprising: a base and a cover,said cover being formed of a dome and a ring wall.
 2. An expanding foodstorage container as in claim 1, wherein: a series of support threads isprovided between said dome and said ring wall.
 3. An expanding foodstorage container as in claim 1, wherein: a series of support threads isprovided on said dome; and a tab is provided on said cover; and said tabis spaced and located to engage said series of support threads; and saidtab and said series of threads are located so that rotation of said domerelative to said ring wall causes said series of threads to rotaterelative to said tab and cause said dome to move longitudinally upwardor downward with respect to said ring wall.
 4. An expanding food storagecontainer as in claim 3, wherein: a resting land is provided to preventcontinued upward or downward movement of said dome with respect to saidring.
 5. An expanding food storage container as in claim 3, wherein: aresting upper land is provided to prevent continued upward or downwardmovement of said dome with respect to said ring; and a resting lowerland is provided to prevent continued upward or downward movement ofsaid dome with respect to said ring.
 6. An expanding food storagecontainer as in claim 3, wherein: a resting lower land is provided toprevent continued upward or downward movement of said dome with respectto said ring.
 7. An expanding food storage container as in claim 6,wherein: a lock button is formed on the dome, and continued rotation ofsaid dome relative to said ring wall causes said tab to ride over saidlock button and due to elastic deformation serve to selectively holdsaid dome against unintended rotation.
 8. An expanding food storagecontainer as in claim 5, wherein: a lock button is formed on the dome,and continued rotation of said dome relative to said ring wall causessaid tab to ride over said lock button and due to elastic deformationserve to selectively hold said dome against unintended rotation.
 9. Anexpanding food storage container as in claim 4, wherein: a lock buttonis formed on the dome, and continued rotation of said dome relative tosaid ring wall causes said tab to ride over said lock button and due toelastic deformation serve to selectively hold said dome againstunintended rotation.